Operating arrangements for closing vacuum chamber access slot sealing valves in vacuum coating apparatus of the multiple-chamber, in-line type, for example, have heretofore involved certain disadvantages including complexity and resultant higher initial costs, comparatively high power rating (and size) of the valve actuator or motive means required for proper valve sealing pressure, and, in the case of the so-called "flapper valve", where the valve member is carried bodily in floating manner on the actuating linkage itself, unsatisfactory slot sealing in the absence of high actuator power.
The present invention is particularly concerned with a materially simplified and comparatively inexpensive valve operating arrangement for improved access slot sealing in vacuum equipment of the character described above.